The present invention relates to a self contained fingerprint ink applicator recording substrate. It is to be noted that, as used herein, the termxe2x80x9cfingerprintxe2x80x9d encompasses prints of an individual""s fingers, hands or feet.
The pattern of ridge endings and ridge bifurcations (minutiae) are highly individualized and are not altered with time. The comparison of such fingerprint patterns have long been recognized as an absolute means of identifying individuals in criminal and noncriminal situations.
To obtain a person""s fingerprint a chemical compound is typically applied to the person""s fingerprint area and subsequently transferred to the surface of the substrate where the print is to be made. Traditionally the chemical compounds for making fingerprints are carbon based inks which comprise finely ground carbon particles suspended in a suitable liquid vehicle. Such inks are sometimes objected to because of the stain left on the person""s finger.
To eliminate or greatly reduce the staining problem inkless or nonstaining ink compounds have been developed which do not rely on carbon particles to form an image of the fingerprint ridge and ridge endings.
Inkless or nonstaining ink technology has traditionally been defined as a color forming chemical reaction, between at least two reagents, that occurs at the time of fingerprint development. The chemical reaction between the two (or more) reagents provides a permanent perceivable colorant product representative of a fingerprint ridge and ridge endings pattern on the recording medium. As a general rule, the two reagents remain isolated from each other until the fingerprint is to be taken. Such nonstaining inks are sometimes hereinafter referred to asxe2x80x9ctwo-phase inksxe2x80x9d.
Typically in a two-phase nonstaining ink system a first reagent (chemical compound), e.g., a color former, is applied to a person""s fingertips and a second reagent, e.g., developer, capable of reacting with the first reagent to produce the colorant product, such as 8-hydroxyquinoline, is pre-applied to or inherent in the recording medium such as the paper or card receiving the print. See U.S. Pat. No. 4,983,415. Also see U.S. Pat. Nos. 4,262,623 and 4,182,261, the contents of which are incorporated herein by reference. Also see my copending PCT application entitledxe2x80x9cMethod of Recording Fingerprints on a Recording Surface Having a Thermosensitive Color Developing Layer Thereonxe2x80x9d filed on even date herewith, the contents of which are also incorporated herein by reference.
A single-phase nonstaining ink has recently been developed by the inventor as described in U.S. Pat. No. 6,488,750 B1. In the single-phase system the two chemical reagents, i.e., a color former and developer are contained in a single reservoir but prevented from reacting while in solution by a chelating agent. This patent is also incorporated herein by reference.
Regardless of the fingerprint system used, i.e, carbon based ink, single-phase or two-phase nonstaining ink, a dispensing pad containing the appropriate ink, and an appropriate recording surface must be available to a person taking the prints. There is a need for a simple and inexpensive applicator which incorporates an ink dispensing pad and a recording surface in a single unit which will accommodate all of the above fingerprinting systems.
A self contained fingerprint ink/inkless reagent applicator, in accordance with the present invention, includes a bottom or base sheet with a adhesive affixed to the bottom thereof and an upper surface suitable for receiving a fingerprint. In the carbon based ink or single-phase nonstaining ink (inkless) system the upper surface may be plain paper. The applicator further includes a top sheet, preferably with an upper ink absorbent surface to accommodate printing and a fluid impermeable bottom surface. An intermediate sheet is sandwiched between the top and bottom sheets. The intermediate sheet contains a liquid absorbent pad, for holding an ink/inkless reagent compatible with the inking system to be employed, disposed along a portion of the upper surface thereof The lower surface of the intermediate sheet is fluid impermeable to deter the ink from migrating into the base sheet. The absorbent pad may be infused with a carbon based ink compound or a developer compound of the two-phase (inkless) system or a combined color former and developer of the single-phase (inkless) system. Where the two-phase chemistry is used the upper surface of the base sheet contains a color former otherwise it may be plain paper. Preferably an anti-wicking material is fused along the perimeter of the absorbent pad to inhibit the ink/inkless reagent from wicking out of the absorbent material during storage.
The applicator is arranged so that at least a portion of the top sheet may be readily removed to expose the ink pad for transferring ink to the fingerprint area and subsequently the portion of the second sheet ink pad to expose the recording surface of the base sheet for receiving the print.